1. Field of the Invention
The present invention relates to a data transmission method and audio/video system, and more particularly, to a data transmission method and audio/video system capable of splitting and synchronizing audio/video data.
2. Description of the Prior Art
Audio and video transmission techniques have wide applications and functions, and are usually applied in audio and video systems, such as a security monitoring system, a projector, or a home theater system. Prior art audio and video systems generally adopt data transmission techniques, such as synchronous, merged audio/video data or asynchronous, split audio/video data.
The security monitoring system usually includes a plurality of monitors and a monitoring center, and the projector is regularly used in a large conference or group presentation. If, in the middle of the conference or the presentation, the presenter changes his position, the computer and the projector may require plugging, unplugging, or turning on and off for a traditional cable projector, which not only wastes time, but also causes inconvenience of use. With the popularity of wireless networking, e.g. wireless fidelity and WiFi, and speed enhancements of embedded central processing units (embedded CPUs), wireless projectors are also becoming more and more popular. The wireless projector links wirelessly to each participant's computer, and thus the presentation can be switched among many presenters at any time, without needing to unplug the connecting line of the screen repeatedly.
Please refer to FIG. 1. FIG. 1 is a functional block diagram of a prior art audio and video system 100. The video and audio system 100 utilizes the data transmission technique capable of synchronizing and merging audio/video data, and includes a wireless transmitter system 110 and a wireless receiver system 120. The wireless transmitter system 110 can receive video input data IVIDEO and audio input data IAUDIO from an audio and video input apparatus 112, utilize an audio and video processing unit 114 for performing operations such as compression and coding for the video input data IVIDEO and the audio input data IAUDIO to generate a corresponding audio and video data stream SA/V, and finally can output the audio and video data stream SA/V through a wireless output end 116. The wireless receiver system 120 can receive the audio and video data stream SA/V transmitted from the wireless transmitter system 110 through a wireless reception end 126, utilize an audio and video processing unit 124 for performing operations such as decompression and decoding for the audio and video data stream SA/V to generate corresponding video output data OVIDEO and audio output data OAUDIO, and finally can output the video output data OVIDEO and the audio output data OAUDIO to an audio and video output apparatus 122. With the audio/video synchronization structure utilized in the prior art audio and video system 100, the audio data and the video data are merged for wireless output during transmission, and thus only the processing approach for the audio and video data in the same receiver system need be considered. If the audio and video input apparatus 112 is a monitor, and the audio and video output apparatus 122 is a display of a monitoring center, the audio and video system 100 can be a security monitoring system; and if the audio and video input apparatus 112 is a notebook computer, and the audio and video output apparatus 122 is a wireless projector, the audio and video system 100 can be a data projection system.
On the other hand, as the bandwidth of the wireless network increases (for example, two wireless network standards: IEEE 802.11a and IEEE 802.11g), applications of the wireless projector gradually evolve from the wireless data projector for the office, conferences and group presentations, to a wireless video projector for a home theater system. In the home theater system, users output video signals through the projector and audio signals to a speaker set.
Please refer to FIG. 2. FIG. 2 is a functional block diagram of a prior art audio and video system 200. The audio and video system 200 utilizes the asynchronous data transmission technique with split audio/video data, and includes a wireless transmitter system 210 and a wireless receiver system 220. The wireless transmitter system 210 can receive video input data IVIDEO and audio input data IAUDIO from an audio and video input apparatus 212, and can utilize a video processing unit 214 for performing operations such as compression and coding for the video input data IVIDEO to generate a corresponding video data stream SV. Finally, the wireless transmitter system 210 can respectively output the video data stream SV and the audio input data IAUDIO through a wireless output end 216 and a wired output end 218 at the same time. The wireless receiver system 220 can respectively receive the video data stream SV transmitted from the wireless transmitter system 210 and the audio input data IAUDIO through a wireless reception end 226 and a wired reception end 228, and can utilize a video processing unit 224 for performing operations such as decompression and decoding for the video data stream SV to generate corresponding video output data OVIDEO. Finally, the wireless receiver system 220 can output the video output data OVIDEO and the audio input data IAUDIO to a video output apparatus 222 and an audio output apparatus 223, respectively. The audio and video system 200 of the present invention can be a home theater system, and the video output apparatus 222 and the audio output apparatus 223 can be a projector and a speaker set, respectively. With the asynchronous and splitting structure for transmitting the audio/video data, the video data and the audio data are split to output wirelessly and over wires, respectively, and during data transmission, the video data stream SV may suffer interference to different extents, such that the video data stream SV and the audio input data IAUDIO received by the receiver system 220 can not be synchronized to each other.